#include <limits>
#include <iostream>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = uint32_t;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208;

int main() {
    int n, c, v;
    cin >> n >> c >> v;
    vector<int> dp(2*n+1, INF<int>);
    dp[1] = 0;
    for (int i = 1; i <= 2*n; ++i) {
        for (int j = 2*i, x = c + v; j <= 2*n; j += i, x += v) {
            dp[j] = min(dp[j], dp[i]+x);
        }
    }
    int ans = INF<int>;
    for (int i = n; i <= 2*n; ++i) {
        ans = min(ans, dp[i]);
    }
    cout << ans << "\n";
    return 0;
}